Transportable container including an internal environment monitor

ABSTRACT

A system is disclosed allowing non-invasive, continuous local and remote sensing of the internal environmental characteristics of transportable containers. The system utilizes a variety of sensors inside the container to sense internal environmental conditions.

CLAIM OF PRIORITY

[0001] This application claims priority to U.S. Provisional patentapplication No. 60/261,035, filed Jan. 10, 2001, entitled SMART PODINCLUDING ONBOARD MONITORING SYSTEM, incorporated herein by reference.

BACKGROUND

[0002] 1. Field of the Invention

[0003] The present invention relates to the manufacture of semiconductorwafers, and in particular to a system allowing non-invasive, continuouslocal and remote sensing of the internal enviromental characteristics oftransportable containers.

[0004] 2. Description of Related Art

[0005] A Standard Mechanical Interface (“SMIF”) system proposed by theHewlett-Packard Company is disclosed in U.S. Pat. Nos. 4,532,970 and4,534,389. The purpose of a SMIF system is to reduce particle fluxesonto semiconductor wafers (“wafers”) during storage and transport of thewafers through the semiconductor fabrication process. This purpose isaccomplished, in part, by mechanically ensuring that during storage andtransport, the gaseous media (such as air or nitrogen) surrounding thewafers is essentially stationary relative to the wafers, and by ensuringthat particles from the ambient atmosphere do not enter the immediatewafer environment. This environment maybe referred to herein as a “cleanenvironment.”

[0006] A SMIF system has three main components: (1) sealed pods used forstoring and transporting wafers and/or wafer cassettes; (2) aninput/output (I/O) minienvironment located on a semiconductor processingtool to provide a clean space (upon being filled with clean air) inwhich exposed wafers and/or wafer cassettes may be transferred to andfrom the interior of the processing tool; and (3) an interface fortransferring the wafers and/or wafer cassettes between the SMIF pods andthe SMIF minienvironment without exposure of the wafers or cassettes tocontaminants. Further details of one proposed SMIF system are describedin the paper entitled “SMIF: A TECHNOLOGY FOR WAFER CASSETTE TRANSFER INVLSI MANUFACTURING,” by Mihir Parikh and Ulrich Kaempf, Solid StateTechnology, July 1984, pp. 111-115.

[0007] SMIF pods are in general comprised of a pod door which mates witha pod shell to provide a sealed environment in which wafers may bestored and transferred. “Bottom opening” pods 100, as illustrated inFIG. 1A, are pods where the pod door 101 is horizontally provided at thebottom of the pod 100 and mates to pod shell 103. The wafers aresupported in a cassette 105 which is in turn supported on the pod door101. “Front opening” pods 110 as illustrated in FIG. 1B, also referredto as front opening unified pods, or FOUPs, include a pod door 111 thatis located in a vertical plane and mates with pod shell 113. The wafers(not shown) are supported either in a cassette (not shown) mountedwithin the pod shell 113, or to shelves 115 mounted within the pod shell113.

[0008] In order to transfer wafers between a bottom opening or frontopening pod and a process tool 505 (FIG. 5) within a wafer fabricationfacility, the pod is typically loaded either manually or automatedlyonto a load port assembly 507 (FIG. 5) which is typically either mountedto, or part of the process tool 505. The load port assembly 507 includesan access port which, in the absence of a pod, is covered by a port door(not shown). Upon loading of the pod on the load port assembly 507, thepod door aligns against the port door in both bottom opening and frontopening systems.

[0009] Once the pod is positioned on the load port assembly 507,mechanisms within the port door unlatch the pod door from the pod shelland move the pod door and port door to a position which allows access tothe wafers by the processing tool 405. The pod shell remains inproximity to the now exposed access port so as to maintain a cleanenvironment that includes the interior of the process tool and the podshell.

[0010] In bottom opening systems, the port door, with the pod door 101and wafer-carrying cassette 105 supported thereon, is lowered into theload port assembly 507. A wafer handling robot within the load portassembly 507 or process tool 505 may thereafter access particular wafersfrom the cassette for transfer between the cassette and the processtool. In front opening systems, the wafer handling robot may access thewafers directly from the pod shell 113 for transfer between the pod 110and the process tool 505.

[0011] Systems of the above type protect against particle contaminationof the wafers. Particles can be very damaging in semiconductorprocessing because of the small geometries employed in fabricatingsemiconductor devices. Typical advanced semiconductor processes todayemploy geometries which are one-half μm and under. Unwantedcontamination particles which have geometries measuring greater than 0.1μm substantially interfere with 1 μm geometry semiconductor devices. Thetrend, of course, is to have smaller and smaller semiconductor devicegeometries which today in research and development laboratories approach0.1 μm and below.

[0012] As device geometries continue to shrink, contamination particlesand molecular contaminants have become an important concern insemiconductor manufacture. There are several sources that causecontamination of semiconductor wafers as they travel through afabrication process. For example, during a manufacturing process,certain gases, fluids, pressures, coherent and incoherent light,vibrations, electrostatic charge, and contaminants may affect the finalyield of semiconductors. Therefore, it is important to control each ofthese parameters within a pod during the fabrication process.

[0013] Sealing the environment within a pod in accordance with SMIFtechnology discussed above has markedly improved a manufacturer'sability to control the environment surrounding semiconductor wafers.However, pods are frequently opened, both automatedly at load portassemblies for wafer transfer, and manually by technicians, for exampleduring pod cleaning. Moreover, pods often include valves for allowingthe transfer of fluids to and from the sealed pod. Each of theseoperations and pod features can be potential sources of contaminants tosemiconductor wafers within a pod.

[0014] It is known to perform wafer lot testing, where random or problempods are selected for internal environmental characteristic testingduring or after device formation on the wafers. While such operationsare capable of identifying problems after they occur, known testingsystems are not intended to pinpoint the time or location at which theproblems occur. Thus, such testing operations are often performed toolate to prevent contamination to a wafer lot. Moreover, where acontaminated pod is allowed to continue through the fabrication process,it often contaminates other processing tools and wafer lots. Furtherstill, conventional testing operations are not intended to identify theareas within the fabrication facility which are introducing contaminantsto the wafers.

[0015] Accordingly, there is a desire to provide an apparatus and methodfor actively monitoring the environment within a pod and processingstations.

SUMMARY OF THE INVENTION

[0016] The invention, roughly described, comprises a transportablecontainer having an internal environment isolated from ambientatmospheric conditions. The transportable container includes a sensorfor monitoring a condition of the internal environmental characteristicwithin the pod and transmitting data representative of the monitoredcondition. The transportable container may also include a power supplyfor providing power to the sensor.

[0017] In a further aspect, a transportable container monitoring systemfor monitoring an internal environmental condition of a transportablecontainer having an internal environment isolated from ambientatmospheric conditions is provided. The transportable containermonitoring system includes a sensor for monitoring the internalenvironmental condition within the container and transmitting datarepresentative of the monitored condition. The system may also include,a transceiver in communication with the sensor for receiving andtransmitting data transmitted by the sensor.

[0018] According to another aspect, a transportable container having aninternal environment isolated from ambient atmospheric conditions isprovided. The transportable container includes a plurality of sensors,each sensor monitoring a distinct internal environmental conditionwithin the transportable container and transmits data representative ofthe monitored condition. A transceiver may also be included in thetransportable container, which receives and transmits the datatransmitted from the sensors.

[0019] According to still another aspect, a sensor network formonitoring internal environment conditions within a transportablecontainer is provided. The sensor network comprises a network bus, atransceiver connected with the network bus, a plurality of network nodesconnected with the network bus, and a plurality of sensors. The sensorsare connected with the network nodes, wherein the sensors monitor theinternal environment conditions within the container, and provide datato the network nodes related to the internal environmental conditions.

[0020] In a further aspect, the invention comprises a method formonitoring an internal environmental condition within a container as thecontainer travels through a fabrication facility. The method comprisesthe steps of monitoring with a sensor the internal environmentalcondition within the container, generating data related to the monitoredcondition, and transmitting the data to a remote location.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will now be described with reference to thefigures, in which:

[0022]FIG. 1A is a schematic view of a bottom opening pod;

[0023]FIG. 1B is a schematic view of a front opening pod;

[0024]FIG. 2 is a schematic perspective view of a pod including aninternal sensor network, in accordance with an embodiment of the presentinvention;

[0025]FIG. 3 is a block diagram of a generic sensor utilizingmicroelectromechanical technology; and

[0026]FIG. 4 is a block diagram of a system architecture, according toan embodiment of the present invention; and,

[0027]FIG. 5 is a block diagram of a wafer fabrication facility thatincludes an embodiment of a transportable pod monitoring system.

DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described hereinafterwith respect to SMIF pods for carrying semiconductor wafers within asemiconductor wafer fabrication process. However, it is understood thatembodiments of the present invention may be used with transportablecontainers other than SMIF pods. For example, embodiments of the presentinvention may be used with unsealed semiconductor lot boxes, pods fortransporting workpieces other than semiconductor wafers, such as, forexample, reticles and flat panel displays, etc. It is further understoodthat embodiments of the present invention comply with and allowcompliance with all applicable SEMI standards. However, it iscontemplated that alternative embodiments of the present invention notcomply with the SEMI standards.

[0029]FIG. 2 illustrates a block diagram of an embodiment of atransportable pod monitoring system 200 including a transportable pod201, and an internal sensor network 202. Various embodiments oftransportable pod monitoring system 200 provide non-invasive, continuouslocal and/or remote sensing of internal environmental conditions oftransportable pods. The transportable pod 201 of FIG. 2 may be any typeof pod, such as a bottom opening pod, a front opening pod, etc. Asindicated above, the type of transportable container is not critical toembodiments of the present invention, and other transportablecontainers, pods, SMIF or otherwise, may be used. The size of theworkpieces transported within the pod may also vary in alternativeembodiments, but may be for example, 200 mm wafers or 300 mm wafers.

[0030] The internal sensor network 202 includes sensors 204, each ofwhich are contained or attached to transportable pod 201, an onboardpower supply 406 (FIG. 4) for providing power to the various sensors,and an internal transceiver 208 for receiving and forwarding data fromsensors 204. In an embodiment, internal transceivers may include memory(not shown) for storing data received from the sensors. Thetransportable pod monitoring system 200 may also include an externaltransceiver 210 for receiving and forwarding data from internaltransceiver 208. As explained hereinafter, internal transceiver 208maybe omitted in alternative embodiments. Additionally, externaltransceiver 210 may be configured as part of a host computer 418 (FIG.4).

[0031] Each of the sensors 204 may be of a known construction and mayrange from relatively simple analog sensors to more complex sensorsoperating according to microelectromechanical (“MEMS”) technology. Morecomplex sensors may include those that combine transducer-sensingelements with Digital Signal Processing (“DSP”) to provide embeddedsampling, analyzing, and reporting of data all within the sensor 204.Examples of such sensors may be those used for photo spectroscopy,gyroscopic orientation, image sensing, chemical sensing and residual gasanalysis. A block diagram of an embodiment of a sensor 304 utilizingMEMS technology is shown in FIG. 3. Additionally, sensors may includememory for storing information.

[0032] Sensors 204 may be distributed around transportable pod 201 in avariety of configurations. Sensors 204 may be mounted to an internalportion of the transportable pod shell 213 in such a way as not tointerfere with the wafers seated within transportable pod 201 or withwafer transfer into or out of pod 201. It is also contemplated that morethan one sensor 204, or sensor inputs, may be provided for sensing asingle internal environmental characteristic at different positions orregions within transportable pod 201.

[0033]FIG. 4 is a block diagram illustrating an embodiment of a sensornetwork 401. It is understood that various control network protocols maybe employed to gather information from the various sensors and transmitthe information to a remote location, such as a fabrication hostcomputer 418. In one embodiment, the control network may be implementedby LonWorks® from Echelon®. Such a system utilizes a plurality of nodes414 a, 414 b, 414 c positioned within transportable pod 201. The nodestie the various sensors 404 a, 404 b, 404 c, power supply 406 andinternal transceiver 408 to each other via a network bus 416. Servers404 a-404 c are similar to and relate to sensors 204 illustrated in FIG.2. Likewise, internal transceiver 404 corresponds to internaltransceiver 208 of FIG. 2.

[0034] Sensors 404 a-404 c include a temperature sensor 404 a forsensing temperature, an accelerometer 404 b for sensing shock andvibration, and a humidity sensor 404 c for sensing relative humiditywithin transportable pod 201. This embodiment is merely exemplary, andtransportable pod 201 may include fewer sensors or may include severaladditional sensors in combination with all, some, or none of, sensors404 a-404 c, for sensing various other internal environmentalcharacteristics.

[0035] Temperature sensor 404 a may be an analog or digital temperaturesensor mounted to the interior of pod 201. It is understood that morethan one such sensor may be used to determine whether temperaturegradients occur within pod 201. If sensor 204 a is an analog sensor, ananalog-to-digital converter may be provided for converting the sampledanalog temperature to a digital representation. Alternatively, a digitaltemperature sensor may be used. For example, an MIC384 Three ZoneThermal Supervisor from Micrel, Inc., San Jose, Calif. 95131 may beused. Such a sensor has a small, low cost package including an on boardprocessor and memory. The sensor 404 a may further include additionalchannels for sensing temperature in different regions of pod 201. Eachchannel may be positioned in different locations within pod 201 forsensing temperature in different regions.

[0036] Temperature sensor 404 a is tied to node 414 a, which may includea processor, such as a Motorola® Neuron 3150, and a sensor businterface, such as an Echelon® FTT-10A twisted pair transceiver, fortransferring the information from temperature sensor 404 a to thenetwork bus 416.

[0037] Accelerometer 404 b may be provided for detecting both shock andvibration within transportable pod 201. An example of such a sensor 404b for use with an embodiment of the present invention is a single axisaccelerometer with analog output, model No. MX1010C from MEMSIC, Inc.,Andover, Mass. 01810. Such sensors are capable of sensing accelerationalong an axis from 1 milli-g to 10 g and converting the measurement to adigital signal via an on board analog-to-digital converter. Sensor 404 bmay include additional channels allowing shock and vibration to besensed along other axes, respectively, within the pod. It is understoodthat other sensors may be used for sensing shock and vibration. Forexample, known piezoelectric sensors which convert acceleration into ameasurable voltage may also be used.

[0038] Accelerometer 404 b is tied to a node 414 b, which preferablyincludes a processor, such as a Motorola® Neuron 3150, and a sensor businterface, such as an Echelon® FTT-10A twisted pair transceiver, fortransferring the information from accelerometer 404 b to network bus416.

[0039] An embodiment of the present invention may also include ahumidity sensor 404 c. Humidity sensor 404 c may be an analog or digitalsensor mounted to the shell of pod 201. One example of a digitalhumidity sensor 404 c for use with an embodiment of the presentinvention is an HIH series relative humidity sensor manufactured byHoneywell, Morristown, N.J. 07962. Humidity sensor 404 c includes asingle channel for sensing the humidity within the pod. Alternativehumidity sensors may include additional channels for sensing humidity indifferent regions of pod 201.

[0040] Humidity sensor 404 c is tied to node 414 c, which preferablyincludes a processor, such as a Motorola® Neuron 3150, and a sensor businterface, such as an Echelon® FTT-10A twisted pair transceiver, fortransferring the information from humidity sensor 404 c to network bus416.

[0041] As indicated above, pod 201 may include additional analog ordigital sensors for sensing other conditions within pod 201 (e.g.:pressure, gas composition, airborne particles, electrostatic buildup,light exposure, vibration, electromagnetic radiation, oxidation changeof wafers, electrolysis, etc.), each of which may be connected to thenetwork via a network node. Pod 201 may also include sensors fordetermining its location within the fabrication facility. Locationsensors may utilize a global positioning system (“GPS”), internaltracking system, or other types of location tracking techniques.

[0042] Pod 201 may also include a reset mechanism, for clearing datagathered by the sensors, and returning the sensors to a neutral state.The reset mechanism may be, for example, a mechanical switch mounted onpod 201, a software reset program provided by the host computer 418 orinternally included in the sensor network 201, or the sensors may resetautomatically at a predetermined location within the fabricationfacility, or upon the occurrence of a predetermined event, such as a podcleaning. Additionally, the reset may be applied to any combination ofthe sensors, and not all sensors need be reset.

[0043] Power supply 406 supplies power to each sensor 404 a-404 c,sensor nodes 414 a-414 c, and internal transceiver 408. The power supply406 may be mounted to an outside surface of the pod shell and connectedto the various sensors via a network bus 416. Power supply 406 mayalternatively be mounted within transportable pod 201. Power supply 406may be of known construction, and may include, for example, a compactpower source such as a rechargeable battery or a nine-volt alkalinebattery. The power supply may further include a regulation circuit, asis known in the art. In an embodiment, one or more sensors may includeonboard power supplies, thus reducing the need for power supply 406 orallowing power supply 406 to be omitted altogether.

[0044] The power supply 406 may provide power via network bus 416 toeach of the sensor nodes as required by the various nodes and sensors.Alternatively, power supply 406 may be tied to a node 414 a-414 c asdescribed above to include the power supply 406 within the sensornetwork, thus allowing the monitoring and control of the power supply406.

[0045] Internal transceiver 408 may be located anywhere on or withintransportable pod 201, and communicates with external transceiver 410.Internal transceiver 408 may communicate with external transceiver 410using any type of wireless data transfer. For example, communication maybe made using electromagnetic radiation, such as infrared (about 10¹³ Hzto about 10¹⁴ Hz), radio waves (about 3 kHz to about 300 GHz) (e.g.:Frequency Modulated (“FM”), Amplitude Modulated (“AM”), radar, RadioFrequency (“RF”), Personal Communication Services (“PCS”), etc.) andvery low frequencies (i.e., about 0 to about 3 kHz). RF systemembodiments may use analog, Code Division Multiple Access (“CDMA”), TimeDivision Multiple Access (“TDMA”), Cellular Digital Packet Data(“CDPD”), or any other RF transmission protocol.

[0046] Transceiver 408 maybe tied to sensor network 401 via a bus master420. Network nodes 414 a-414 c may be configured as a master-slavenetwork, wherein bus master 420 functions as a gateway or routerreceiving data from each of the sensor nodes 414 a-414 c and forwardingthe information to external transceiver 410. In an alternativeembodiment, the individual nodes may be sufficiently sophisticated sothat the network can be configured as a pier-to-pier network. In thisembodiment, transceiver 408 and bus master 420 may be omitted and eachof the individual sensor nodes 414 a-414 c would communicate directlywith external transceiver 410 using any of the above electromagneticradiation frequencies.

[0047] Bus master 420 incorporates back-to-back network nodes 414 a-414c to form a gateway or router passing information through a datacollection and a Digital Signal Processor (“DSP”) such as, for example,model TMS 320C30 by Texas Instruments®.

[0048] Transmission of data to external transceiver 410, whether it istransmitted from internal transceiver 408, or directly from the sensors404 a-404 c, may be transmitted constantly or intermittently. If thedata is transmitted intermittently, it may be stored, either within thesensor's memory, or within the memory of internal transceiver 408 anddelivered in packets using, for example, CDPD techniques.

[0049] Alternatively, data may only be transmitted if the correspondinginternal environmental conditions are outside of a predefined desiredoperating range. In such an embodiment, the data itself may betransmitted or just an alert signal maybe transmitted, therebyidentifying that an internal characteristic within the pod is outsidethe desired operating range. In an embodiment, an audible alarm may beactivated, thereby alerting the fabrication facility operators that aninternal environmental condition for pod 201 is not within the desiredoperating range.

[0050] Additionally, if sensor data is stored on a memory within saidpod 201, the data may be read by a computer at a later time to determinethe type of environment condition which exceeded the operating range,and also information regarding the time and location within the facilitywhere the contamination occurred.

[0051] In another embodiment, data is transmitted from pod 201 inresponse to an external request command. For example, host computer 418(FIG. 4) sends status request commands to pod 201 at a predeterminedtime interval, such as every 10 seconds. In response to the statusrequest commands pod 201 transmits the current sensor data to the hostcomputer 418.

[0052] Some FOUPs currently operate with an IR tag or RF pill which iscapable of receiving information regarding the various workpieces withinthe pod and relaying that information to fabrication host computer 418to allow identification of the workpieces within a pod as they travelbetween the various stations within the fabrication facility. Such IRtags, and systems making use thereof, are described for example in U.S.Pat. Nos. 5,097,421, 4,974,166 and 5,166,884 to Maney et al. Such RFpills, and systems making use thereof, are described for example in U.S.Pat. Nos. 4,827,110 and 4,888,473 to Rossi et al., and U.S. Pat. No.5,339,074 to Shindley. Each of the above-identified patents are assignedto the owner of the present invention, and each is incorporated byreference in its entirety herein.

[0053] In an alternative embodiment of the present invention, the IR tagor RF pill performs the functions of transceiver 408 to receive datafrom the various sensor nodes 414 a-414 c and relay that information toexternal transceiver 410 and/or host computer 418.

[0054] The various nodes 414 a-414 c and bus master 420 maybe connectedto each other via the network bus 416, which may comprise a micro 5-wirelink bus capable of communicating power (+v, −v) and transmit andreceive (tx, rx) signals, and which may include an electromagneticprotection shield. The network bus 416 may be a thin flexible ribbon,which is adhered to or embedded into the shell of transportable pod 201during manufacturing with taps for the various nodes. Alternatively, thenetwork bus 416, sensors 404, and internal transceiver 408 may beadhered to a currently-existing pod and hermetically sealed passages(herein referred to as “taps”) for the various nodes created in the pod.Additional taps may also be formed in pod 201 to allow introduction ofadditional sensors at a later time. In embodiment, when a sensor isadded, the portion of the sensor inserted into the tap punctures amembrane of the network bus 416, thereby adding the sensor to the sensornetwork.

[0055] Network bus 416 may pass through pod shell 213 at a tap to allowtransfer of power and information signals between the interior andexterior of the pod. Network bus 416 is merely one example forconnecting the various nodes in the sensor network. Alternative,communication protocols include electromagnetic frequencies, optical, orother means using known topologies such as star, loop, daisy-chain orfree-type configurations.

[0056] As indicated above, FIG. 4 is merely one embodiment of thepresent invention for communicating information relating to internal podcharacteristics to a fabrication host computer 418. It is understoodthat industry standard networks other than LonWorks® may be used toimplement the sensor network 401, including for example a ControllerArea Network (“CAN”) bus or TCP/IP ethernet.

[0057]FIG. 4 further illustrates external transceiver 410 which islocated remote from transportable pod 201, on for example, a load portassembly 507 (FIG. 5), a support surface on which transportable pod 201is seated, mounted within a fabrication room 503 a-503 d (such as on theceiling or wall), etc.

[0058] In an embodiment, each processing tool 505 may include anexternal transceiver 410 which receives information from internaltransceiver 408. This information may then be relayed to host computer418 via wired or wireless transmission, or processed locally. Due to theclose proximity of internal and external transceivers when the pod isseated on the load port assembly, such an embodiment allows for the useof higher frequency transmission systems which typically deteriorateover long ranges of transmission. Additionally, in fabricationfacilities which include several different fabrication rooms, often onseveral different floors or in different buildings, having an externaltransceiver 410 on the processing tool allows information to be relayedto host computer 418 (which may be located at a remote location or inone of the fabrication rooms) from each of the rooms and/or buildings.

[0059] Additionally, the external transceiver located on a processingtool may be in communication with the respective processing tool and ifinformation is received from pod 201 that a contaminant has beenintroduced, the processing tool may immediately be deactivated withouthaving to relay the information to a host computer 418. Immediatelydeactivating the processing tool may reduce the amount of contaminationintroduced to the processing tool and/or may also reduce the amount ofcontaminated wafers.

[0060] Internal transceiver 408 broadcasts to different externaltransceivers 410 as the transportable pod 201 including the internaltransceiver 408 moves around the fabrication facility. Externaltransceiver(s) 410 may be tied to a remote network node including aprocessor and bus interface as described above.

[0061] The information received by external transceiver 410 is passed tothe network node through a data collection and DSP processor, such asfor example model TMS 320C30 by Texas Instruments®. The remote networknode may also include a standard RS-232 serial communication port totransfer the sensor information to the fabrication host computer 418. Itis understood that various other known communication protocols maybeused instead of an RS-232 interface in alternative embodiments, such aswireless transmission.

[0062] In an alternative embodiment, information may be relayed directlyto host computer 418 from nodes 404 a-404 c, thereby eliminating theneed for external transceiver 410.

[0063] Host computer 418 is configured to receive data from eachtransportable pod 201 within the fabrication facility. Host computer 418may continuously cycle through data for each transportable pod 201, sothat readings from a pod may be detected in real time.

[0064] In an alternative embodiment, host computer 418 is configured topoll pods 201, sending a status request command, as they travel througha fabrication process. In response to the polling, each pod 201transmits information related to its condition and location. Activelypolling the pods 201 provides an added security measure. If pod 201 doesnot respond to the poll, either the pod is defective or it is not withinthe communication range of host computer 201, or it has been removedfrom the fabrication facility.

[0065] Once data from a particular pod is received in host computer 418,host computer 418 may perform any of various operations. For example, ifone or more of the measured internal pod characteristics are outside ofan expected range, host computer 418 may direct that pod 201 be manuallyor automatedly taken off-line and isolated for inspection. As thepresent invention provides pod internal environmental measurements inreal time, a transportable pod 201 exhibiting abnormal readings can bequickly identified and isolated upon entry of the contaminant to the podenvironment. Thus, the system according to an embodiment of the presentinvention prevents the spread of contamination by isolating acontaminated pod before it is exposed to other tools or workpieces.

[0066] It is a further advantage of the present invention that data fromtransportable pods can be used to gather information about individualprocess tools in the fabrication facility, and can also identify thesource of a particular contaminant within the fabrication facility. Ifit is evident over time that pods frequently exhibit abnormal readingsafter processing at a particular tool, an embodiment of the presentinvention identifies this situation and the tool may be taken off-linefor inspection and maintenance. While prior art systems allow fortesting and monitoring of wafer lots, this is performed either bymanually or automatedly taking the pods to a metrology tool, where thepods are opened and the workpieces tested for contaminants. Not only doembodiments of the present invention perform such testing on acontinuous basis, they do so in a non-invasive manner without having toopen the pods and without slowing the processing throughput of the waferlot.

[0067] Host computer 418 can also store the data from a particular podalong with that pod's identification and/or path through the fabricationfacility. This data can be used for statistical process control byshowing how a pod and/or a process tool performs over time. Fabricationfacility operators can use this information to statistically identifywhen pod/tool maintenance is required, as well as identify how well apod/tool is performing relative to others. This information may also beused for security measures for tracking the location of pod 201.

[0068] Host computer 418 may additionally be connected to an Intranet orInternet network via a standard ethernet connection. Thus, pod and toolperformance from one fabrication facility can be monitored andcontrolled in real time by an operator who may be thousands of milesaway. This connection also gives an operator the ability to compare podand tool performance across a large number of semiconductor waferfabrications.

[0069] In an embodiment of the present invention, the sensor networkprovides data as to the internal environmental characteristics of asealed pod as it travels through the semiconductor fabrication process.However, in an alternative embodiment, the present invention maybe usedto sense the internal environmental characteristics of a load portminienvironment on which a pod is seated. In particular, as explained inthe Background of the Invention section, in order to transfer workpiecesbetween a pod and a process tool, the pod is loaded onto a load port,which separates the pod door from the pod shell to provide access to theworkpieces therein. The pod shell is generally kept in position on theload port to seal the access port vacated by the port door. Inaccordance with this alternative embodiment, while positioned on theload port, the sensors in the pod shell can provide data relating to theinternal environmental characteristics of the load port minienvironmentand/or process tool to which the minienvironment is affixed.

[0070]FIG. 5 illustrates a typical fabrication facility 500, includingan embodiment of a transportable pod monitoring system 200. Fabricationfacility 500 may include a main corridor 501, and several processingrooms 503 a, 503 b, 503 c, 503 d, 503 e, and 503 f. Each processing roommay contain one or more processing tools, such as processing tool 505.As discussed above, a processing tool 505 typically includes a load portassembly 507 for loading and unloading pods.

[0071] According to an embodiment of the present invention, thefabrication facility 500 includes a transportable pod monitoring system200 (FIG. 2) for monitoring the movement of transportable pods, such aspod 511 throughout the fabrication facility 500. As discussed above,there are many different configurations which maybe used to monitortransportable pod 511. For example, each processing room 503 a-503 f mayinclude an external transceiver 510 a which receives informationtransmitted from pods which are within that particular room.Alternatively, each load port assembly 507 may include an externaltransceiver, such as external transceiver 510 b which receivesinformation from a pod 511 which is located on that particular load portassembly 507. Additionally, an primary external transceiver, such asexternal transceiver 510 c, located in main corridor 501 may be used toreceive transmissions from all pods contained in fabrication facility500.

[0072] Information received by external receivers 510 a-510 c may betransmitted to a host computer, such as host computer 520 a located inthe fabrication facility 500, or to a host computer 520 b located at aremote location 525, which may be thousands of miles away.

[0073] Although the invention has been described in detail herein, itshould be understood that the invention is not limited to theembodiments herein disclosed. Various changes, substitutions andmodifications may be made thereto by those skilled in the art withoutdeparting from the spirit or scope of the invention as described anddefined by the appended claims.

We claim:
 1. A transportable container having an internal environmentisolated from ambient atmospheric conditions, comprising: a sensor,monitoring a condition of said internal environment, and transmittingdata related to said monitored condition; and, a power supply, providingpower to said sensor.
 2. The transportable container of claim 1, whereinsaid sensor continuously and non-invasively monitors said condition ofsaid internal environment within said container.
 3. The transportablecontainer of claim 1, wherein said data is transmitted usingelectromagnetic radiation.
 4. The transportable container of claim 3,wherein said electromagnetic radiation is in a frequency range of about3 kHz to about 300 GHz.
 5. The transportable container of claim 1,wherein said sensor comprises a memory for storing said data related tosaid monitored condition.
 6. The transportable container of claim 1,further comprising: an internal portion of said transportable container,wherein said sensor is mounted to the internal portion of saidtransportable container.
 7. The transportable container of claim 1,further including a second sensor, monitoring a condition of saidinternal environment within said transportable container, andtransmitting data related to said monitored condition.
 8. Thetransportable container of claim 1, wherein said sensor includes aplurality of sensor inputs positioned at respective distinct locationswithin said transportable container, each said sensor input monitoringsaid condition of said internal environment at said respective distinctlocations within said container.
 9. The transportable container of claim1, further including: a transceiver in communication with said sensor,receiving and transmitting said data transmitted by said sensor.
 10. Thetransportable container of claim 9, wherein said transceiver isconnected with said transportable container, and wherein said data istransmitted over a network bus.
 11. The transportable container of claim9, wherein said data is transmitted between said sensor and saidtransceiver using electromagnetic radiation.
 12. The transportablecontainer of claim 11, wherein said electromagnetic radiation is in afrequency range of about 3 kHz to about 300 GHz.
 13. A transportablecontainer monitoring system for monitoring an internal environmentalcondition of a transportable container having an internal environmentisolated from ambient atmospheric conditions, the transportablecontainer monitoring system comprising: a sensor, monitoring saidinternal environmental condition, and transmitting data representativeof said monitored internal environmental condition; and, a transceiverin communication with said sensor, receiving and transmitting saidtransmitted data.
 14. The transportable container monitoring system ofclaim 13, wherein said transportable container is positioned on aprocessing tool, and wherein said transceiver is operatively connectedwith said processing tool.
 15. The transportable container monitoringsystem of claim 14, wherein said transceiver provides said data to saidprocessing tool, and said processing tool deactivates if said data isnot within a desired operating range.
 16. The transportable containermonitoring system of claim 13, further including: a second transceiver,at a location external to said transportable container, for receivingand transmitting said data transmitted by said transceiver.
 17. Thetransportable container monitoring system of claim 16, furtherincluding: a host computer receiving and processing said datatransmitted from said second transceiver.
 18. The transportablecontainer monitoring system of claim 17, wherein said host computer isat a remote location relative to said transportable container.
 19. Thetransportable container monitoring system of claim 17, wherein said hostcomputer determines if said monitored internal environmental conditionwithin said transportable container is within a desired operating range.20. The transportable container monitoring system of claim 19, whereinsaid container is positioned on a processing tool, and wherein said hostcomputer deactivates said processing tool if said internal environmentalcondition is not within said desired operating range.
 21. Atransportable container having an internal environment isolated fromambient atmospheric conditions, comprising: a plurality of sensors, eachsensor monitoring an internal environmental condition within saidtransportable container; a transceiver in communication with saidplurality of sensors, receiving and transmitting said data transmittedby said plurality of sensors; and, a power supply, providing power tosaid at least one sensor and said transceiver.
 22. The transportablecontainer of claim 21, wherein at least one of said sensors in saidplurality of sensors is selected from a group comprising: a temperaturesensor; a humidity sensor; and an accelerometer sensor.
 23. Thetransportable container of claim 21, wherein at least one of saidplurality of sensors includes a plurality of sensor inputs, mounted withsaid internal portion of said container at distinct locations, sensingan internal environmental condition within said container at saidrespective distinct locations.
 24. The transportable container of claim21, wherein said communication between said plurality of sensors andsaid transceiver is performed over a network bus.
 25. A transportablecontainer sensor network, for monitoring internal environmentalconditions within a transportable container, comprising: a network bus;a transceiver, connected with said network bus; a plurality of networknodes, connected with said network bus; and, a plurality of sensors,connected with said network nodes, wherein said sensors monitor saidinternal environment conditions within said transportable container, andprovide data to said network nodes related to said internal environmentconditions.
 26. The transportable container sensor network of claim 25,wherein said plurality of network nodes are configured as a master-slavenetwork, and wherein said network bus functions as a gateway.
 27. Thetransportable container sensor network of claim 25, wherein saidplurality of network nodes are configured as a pier-to-pier network. 28.A method for monitoring an internal environmental condition within atransportable container having an internal environment isolated fromambient atmospheric conditions, comprising the steps of: monitoring witha sensor, said internal environmental condition within saidtransportable container; generating data related to said monitoredcondition; and, transmitting said data.
 29. The method of claim 28,further including the steps of: receiving said data at a locationexternal to said transportable container; and, processing said data todetermine if said internal environmental condition is within a desiredoperating range.
 30. The method of claim 28, wherein said step ofmonitoring includes monitoring a plurality of internal environmentalconditions with a plurality of sensors.
 31. The method of claim 28,wherein said data is transmitted using electromagnetic radiation. 32.The method of claim 31, wherein said electromagnetic radiation is in afrequence range between about 3 kHz to about 300 Ghz.
 33. The method ofclaim 28, further including the steps of: determining whether saidinternal environmental condition is within a desired operating range;and, alerting an operator if it is determined that said internalenvironmental condition is not within a desired operating range.
 34. Themethod of claim 33, wherein said step of determining whether saidinternal environmental condition is within a desired operating rangeincludes the step of: processing said data related to said internalenvironmental condition.